In the oil industry, and other similar industries, there is sometimes a requirement to operate equipment at long distances from any existing source of power. This means that both power and communications each have to be arranged by cable or radio links. This can be problematic as long lengths of cable are costly and also can have high resistances leading to high voltage drops, meaning that very high voltages may be required for equipment to function. Communications also suffer due to the resistance of the long wires.
An alternative approach to this is to locally power the device with a battery, but the power output of a battery tends to become impaired due to power leakage and performance decay at high temperatures.
Currently few electrically powered devices are deployed into down-hole environments but the above issues have been addressed in the following ways:                1. High voltages are used to overcome the resistance of the cabling so as to give the down-hole device adequate power;        2. Systems that are only deployed for a short period of time or only operate for “one shot” are powered by on-board batteries, but these systems may degrade in the higher temperature situations.        